Specific immunotherapy has long-term preventive effect of seasonal and perennial asthma: 10-year follow-up on the PAT study

Allergy. 2007 Aug;62(8):943-8. doi: 10.1111/j.1398-9995.2007.01451.x.


Background: 3-year subcutaneous specific immunotherapy (SIT) in children with seasonal allergic rhinoconjunctivitis reduced the risk of developing asthma during treatment and 2 years after discontinuation of SIT (5-year follow-up) indicating long-term preventive effect of SIT.

Objective: We evaluated the long-term clinical effect and the preventive effect of developing asthma 7-years after termination of SIT.

Methods: One hundred and forty-seven subjects, aged 16-25 years with grass and/or birch pollen allergy was investigated 10 years after initiation of a 3-year course of SIT with standardized allergen extracts of grass and/or birch or no SIT respectively. Conjunctival provocations were performed outside the season and methacholine bronchial provocations were performed during the season and winter. Asthma was assessed by clinical evaluation.

Results: The significant improvements in rhinoconjunctivitis and conjunctival sensitivity persisted at the 10-year follow-up. Significantly less actively treated subjects had developed asthma at 10-year follow-up as evaluated by clinical symptoms [odds ratio 2.5 (1.1-5.9)]. Patients who developed asthma among controls were 24/53 and in the SIT group 16/64. The longitudinal treatment effect when adjusted for bronchial hyper-responsiveness and asthma status at baseline including all observations at 3, 5 and 10 years follow-up (children with or without asthma at baseline, n = 189; 511 observations) was statistically significant (P = 0.0075). The odds ratio for no-asthma was 4.6 95% CI (1.5-13.7) in favor of SIT.

Conclusion: A 3-year course of SIT with standardized allergen extracts has shown long-term clinical effects and the potential of preventing development of asthma in children with allergic rhinoconjunctivitis up to 7 years after treatment.

Clinical implication: Specific immunotherapy has long-term clinical effects and the potential of preventing development of asthma in children with allergic rhino conjunctivitis up to 7 years after treatment termination.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Allergens / immunology
  • Allergens / therapeutic use*
  • Antigens, Plant
  • Asthma / complications
  • Asthma / immunology
  • Asthma / prevention & control*
  • Betula / immunology
  • Bronchial Provocation Tests / methods
  • Desensitization, Immunologic / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Longitudinal Studies
  • Male
  • Odds Ratio
  • Pain Measurement / methods
  • Plant Proteins / immunology
  • Plant Proteins / therapeutic use
  • Poaceae / immunology
  • Pollen
  • Rhinitis, Allergic, Seasonal / complications
  • Rhinitis, Allergic, Seasonal / immunology
  • Rhinitis, Allergic, Seasonal / prevention & control*
  • Risk Factors
  • Skin Tests / methods
  • Time


  • Allergens
  • Antigens, Plant
  • Phl p V protein, Phleum pratense
  • Plant Proteins
  • Bet v 1 allergen, Betula